Combination oil and gas burner construction



March 14, 1967 R. REICHHELM COMBINATION OIL AND GAS BURNER CONSTRUCTION 3 Sheets-Sheet 1 Filed May 5, 1965 AIR LIQUID FUEL INVENTOR. Roberr Reichhelm AT TO RNEY March 14, 1967 R. REICZHHELM COMBINATION OIL AND GAS BURNER CONSTRUCTION SSheets-Sheet 2 Filed May 5, 1965 FIG.4

March 14, 1967 R. REICHHELM COMBINATION O IL AND GAS BURNER CONSTRUCTION 3 Sheets-Sheet 5 FIG.6

Filed May 5, 1965 FIG.9

United States Patent 3,308,868 COMBINATION OR. AND GAS BURNER CONSTRUCTION Robert Reichhelm, Wallingford, Conn., assignor to Combustion Efficiency Corporation, Darien, Conn. Filed May 5, 1965, Ser. No. 453,354 17 Claims. (Cl. 15811) This invention relates to a burner construction and more particularly to a burner capable of effectively burning either a liquid and/or a gas fuel. More specifically this invention is directed to a burner construction arranged to gasify a liquid fuel prior to burning the same so as to effect a more complete and efficient combustion of such liquid fuel and/ or wherein a gaseous fuel may be burned either in combination with the gasified liquid fuel or separately as an alternate fuel through the same burner tip.

Heretofore, many efforts have been made in an attempt to develop a highly efficient liquid fuel burner and/ or a combination gas and oil burner. In the known liquid fuel burners various means have been employed to mix the liquid fuel with the necessary combustion air to attain a good combustible mixture. The known efforts generally utilize an atomizing means to develop a fuel spray or mist which could then be more readily mixed or combined with the necessary combustion air to create the combustible mixture. However, even with the best known atomizing means, the liquid fuel frequently was not able to become so intimately mixed with the combustion air that complete combustion of the fuel could be achieved. As a result, maximum efficiency and economy of the fuel was not realized.

The incomplete combustion resulting from such efforts created additional problems of maintenance. The incomplete combustion of liquid fuel resulted in the formation and accumulation of residue requiring frequent cleaning of the burner parts in order to maintain the burner at optimum operating efficiency. Consequently, the known oil burner constructions have never achieved the cleanliness or efiiciency of operation comparable to that of gas burners.

The problems of efiicient combustion and maintenance of liquid fuel burners becomes even more aggravated when relatively low grade fuel oils, as for example fuel oil grade 6, and lower, are being consumed.

In combination burners wherein it is desirable to burn either a liquid and/or gaseous fuel, there has been presented the further problem that heretofore separate and distant burners or burner nozzles were required for burning each of the respective liquid or gaseous fuels. Consequently, such burners were further complicated because separate and distinct controls were required with the respective distinct burner nozzles to attain the desired combustion of the respective liquid and gaseous fuels. In combination gas and oil burners experience has shown that when only one or the other of the respective fuels was separately burned, the heat from the operating burner nozzle and of the combustion chamber adversely effected the burner nozzle which was not operating. Consequently, when the non-operating burner tip or nozzle is exposed to the heat of the combustion chamber it was sub jected to severe attrition that required constant and diligent maintenance to maintain the same at its optimum operaing efiiciency. Non use of such burners further minimized the useful life of such burner tips. As a result, the above noted disadvantages greatly increase the initial capital expenditures as well as operating and maintenance costs of the known combination gas and oil burners.

It is, therefore, an object of this invention to provide a burner constructed and arranged to effect complete gasification of the liquid fuel prior to burning of the same so that the eificiency and completeness of combustion is comparable to that of a gas burner.

It is another object of this invention to provide a liquid fuel burner construction in which a relatively low grade liquid fuel may be satisfactorily and substantially completely consumed with a maximum of efliciency.

It is another object of this invention to provide acombination gas and oil burner in which the respective liquid and gas fuels may be burned either separately and/ or in combination through the same burner tip.

Another object of this invention is to provide the burner construction in which the liquid fuel is transformed into a substantially gaseous state at a position remote from the burner tip by preheated combustion air and which fuel in its gaseous state is intimately mixed therewith to form a combustible gaseous mixture which is subsequently consumed at the burner tip.

It is another object of this invention to provide a liquid fuel burner and gasifier capable of efficiently burning relatively low grade fuel having means for periodically scavenging the gasifier so as to maintain it relatively free of residue throughout the entire operating life of the burner.

Another object of this invention is to provide a combination gas and oil burner that is relatively simple in construction, relatively inexpensive to fabricate, and positive in operation.

It is another object of this invention to provide a burner construction in which means are provided for preheating the combustion air to a temperature which is greater than the vaporizing temperature of the liquid fuel to be consumed, but lower than the cracking temperature of the liquid fuel whereby the preheated combustion air is utilized to transform the liquid fuel into its gaseous state and intimately intermingle therewith to form a combustible mixture which is then supplied to a burner tip.

Another object of this invention is to utilize the improved burner construction of this invention for space heater application.

Another object of this invention is to provide a combination gas and/or oil fired space heater having a mantle construction having integrally formed therein an air preheater by which the combustion air is preheated prior to the mixing thereof with the liquid fuel.

Another object of this invention is to provide a combination gas and/ or oil burner having a burner tip or nozzle common to the burning of either a liquid or gaseous fuel, either separately and/or in combination.

The foregoing objects and other features and advantages are attained by a burner construction which comprises a means defining a gasifying chamber remotely disposed to the burner nozzle of the burner. An air preheater is provided for preheating the air necessary for combustion. In accordance with this invention the air preheater is proportioned so that combustion air flowing therethrough is preheated to a temperature which is greater than that of the vaporizing temperature of fuel being consumed, but less than the cracking temperature of such fuel. The arrangement is such that the preheated combustion air is introduced into the gasifying chamber wherein it is permitted to intimately mix with the liquid fuel being introduced therein, the heat of the preheated combustion air being utilized to transform the liquid fuel into its gaseous state. The combustible mixture thus formed is directed to the burner nozzle where it is ignited.

To render the burner construction a combinati-on gas and oil burner a means is provided for supplying a gaseous fuel to the gasifying chamber. Accordingly, either a gas and/or a liquid fuel may be supplied to the gasifying chamber, from whence the respective fuels in their re- .pective gaseous state are then directed to the burner so hat each of the fuels may be burned either separately md/ or in combination through the same burner tip. In his manner, the tip of the burner is adequately cooled Jy the flow fuel mixture flowing therethrough regardless )f which type of fuel being burned.

In one form of the invention illustrated, the air preie'ater comprises a heat exchanger constructed with a flexble corrugated surface circumscribing the burner tip in teat transfer relationship thereto. The arrangement is iuch that all the air necessary to effect the gasification of he liquid fuel and to render it a combustible mixture is lirected through the air heater and into the gasifying cham- Jer. In this form of the invention the velocity of the air s maintained at a point sufficient to prohibit flash-back :herethrough.

In another form of the invention the preheater for the :ombustion air comprises a heat exchanger of annulus form made of ceramic or other heat resistant material which is disposed in heat transfer relationship with respect to the burner tip. In this form of the construction, ;he annulus is so formed so that all the air necessary for :ombustion is preheated prior to the intermingling thereof with the liquid fuel.

In still another form of the invention, the means for effecting preheating of the combustion air comprises a cylindrical annulus which is ada-ped to circumscribe the burner nozzle and which annulus is disposed within a combustion chamber of a furnace or the like. The cylindrical annulus is provided with an inlet and outlet to permit the air heated therein to circulate therethrough. The outlet of the annulus is connected to a pair of branch lines, one of which is arranged to direct a portion of the preheated air to the gasifying chamber and the other line being arranged to direct the remaining portion of the preheated air to the burner nozzle. Valve means are interposed in the respective branch lines to effect the desired proportioning of the preheated combustion air to either the gasifying chamber and/ or to the burner nozzle.

In accordance with this invention a heater means for effecting initial gasification of the liquid fuel is provided in the gasifying chambers of the respective burner modifications to effect the initial gasification of the liquid fuel on start-up of the burner. Consequently, once the burner has been placed in operation, the use of the heater means is no longer required; the continued gasification of the liquid fuel being affected by the circulation of preheated combustion air through the gasifying chamber during the operation of the burner.

To adapt each of the respective embodiments for burning relatively low grade liquid fuel, e.g. No. 6 fuel oil and lower, an igniter means is disposed within the gasifying chamber. The arrangement and operation of the igniter is such that it is periodically energized to ignite any accumulation of residue within the gasifying chamber. Accordingly, the periodic scavenging of the gasifying chamber by igniting of the residue therein maintains the gasifying chamber free of accumulating residue throughout the operating life of the burner.

In another form of the invention the concepts disclosed herein are utilized in a space heater application in which the mantle for radiating the heat is specifically constructed and arranged to incorporate therein the air heating means by which the combustion air necessary to effect gasification of the liquid fuel is heated.

A feature of this invention resides in a burner construction in which relatively -low grade fuel oils may be efficiently burned by gasification of the same in a gasifying chamber prior to burning and which chamber is provided with means for periodic scavenging the same of any accumulating residue so as to maintain it in a relatively clean state throughout the operating life of the burner.

Another feature of this invention resides in the provision of a combination gas and -oil burner in which either gas and/ or oil is burned through the same burner tip or nozzle.

Other features and advantages will become more readily apparent when considered in view of the drawings and specifications in Which:

FIGURE 1 is a perspective view of a combination gas and oil burner utilizing the concepts of the instant invention.

FIGURE 2 is an enlarged detailed sectional view of the burner tip utilized in the construction of the burner disclosed in FIGURE 1.

FIGURE 3 is a partial top view of the burner tip of FIGURE 2.

FIGURE 4 is a vertical section view illustrating a modified form of the invention.

FIGURE 5 is a top plan view of the air preheating means utilized in construction of the burner illustrated in FIGURE 4.

FIGURE 6 illustrates another modified burner arrangement in accordance with this invention.

FIGURE 7 is a sectional view taken along line 77 on FIGURE 6.

FIGURE 8 is a detailed side elevation view of FIG- URE 7 having parts thereof shown in section.

FIGURE 9 is a modified form of the invention utilized in a space heater application.

FIGURE 10 is a elevation view of the mantle construction which is adapted to be utilized in conjunction with the burner arrangements disclosed in FIGURES 1 and 4 to transform the same into a space type heater.

Referring to the drawings, there is shown in FIGURES 1, 2, and 3 a burner construction 26 embodying the concepts of the instant invention. As shown therein the burner construction 20 comprises a means defining a gasifying chamber or compartment 21 which is remotely disposed from the burner or burner nozzle 22. The gasifying chamber 21 is defined by :a bottom wall 23 having a connected circumscribing sidewall 24 preferably formed of a suitable refractory or heat resistant type of material to prevent any heat loss therethrough. The top of the chamber 21 thus defined is closed by a suitable cover plate 25.

As shown a liquid fuel supply conduit 26 is connected in communication with the interior of the gasifying chamber 21. A suitable control valve 27 may be interposed into the liquid fuel conduit or line 2-6 to control the flow of liquid fuel to the gasifying chamber.

Spaced above the gasifying chamber is a combustion chamber or burner pot 28. As shown, a burner nozzle or tip 22 is supported on the end of a fuel pipe 29 within the combustion chamber or burner pot, the inlet end of the fuel pipe being connected in communication with the gasifying chamber 21. As best seen in FIGURES 2 and 3 the burner tip 22 comprises a spud 22A provided with a tapped opening 30 by which it may be suitably secured to the upper end of a fuel supply pipe 29. Accordingly, the burner tip or spud 22A is provided with a distribution chamber 31 which connects into communication with a plurality of radially extending passageways 32 that tenninate in a port or opening 33 formed along the sidewalls of the burner tip. As best seen in FIGURE 2, the sidewalls of the burner tip 22A incline upwardly and outwardly. Thus a plurality of burner ports 33 are circumferentially spaced intermediate the height of the sidewall of the spud 22A.

Disposed immediately above and adjacent the burner tip 22A there are provided the electro means or igniter 34 whereby the ignition of the fuel may be attained.

In accordance with this invention a means for preheating combustion air is provided, the heat of such air being utilized to effect gasification of the liquid fuel in chamber 21. In the illustrated form of the invention the preheater 35 is disposed in heat transfer relationship to the'burner tip 22A. As best seen in FIGURE 1 the preheater comprises a flexible conduit or the like provrded with corrugated heat transfer surface that circumscribes the burner tip 22A. One end 35A of the conduit is adapted to connect up to a source of combustion air, e.g. a force draft fan or blower 36 by which the necessary combustion air at ambient air temperature is supplied to the inlet of the air preheater 35. The other or discharge end 35B of the preheater is connected into communication with the gasifying chamber 21. Accordingly, it is to be noted that all the air necessary for combustion of the liquid fuel is directed through the preheater 35 and into the gasifying chamber.

In accordance with this invention the temperature of the air flowing through the preheater may be determined by maintaining the ratio of the heat exchange surface of the preheater 35 to ambient air temperature sufiicient to heat the air flowing therethrough to a range of 600 F. to 900 F. The temperature of the air thus preheated is greater than the vaporizing temperature of the liquid fuel oil, but less than the cracking temperature of such fuel. During burner operation, the preheated air, ranging between 600 F. and 900 F is thus intimately mixed with the liquid fuel within the gasifying chamber 21 and the heat of the air is utilized to effect a transformation of the liquid fuel from its liquid to its gaseous state. Thus a combustible gaseous fuel and air mixture is attained within the chamber. The blower is operated so that the velocity of the air through the gasifying chamber is maintained at a rate to prohibit flashback. Accordingly, the combustible mixture is delivered from the gasifying chamber 21 to the burner tip 22A through a supply conduit or pipe 29 and from which the mixture is distributed to the respective burner ports 33.

To provide heat necessary to effect the gasification of the liquid fuel upon start-up, the gasifying chamber has disposed therein a heater 37 preferably an electric band or cartridge type heater. In the illustrated form of the invention a band type heater 37 is connected to an external source of electrical energy 38. Upon start-up of the burner 21, the energization of the heater will raise the temperature in the chamber sufficiently high to effect gasification of the fuel.

Included in the heater circuit 39 is a thermostatic switch 40 which is arranged to assure the maintenance of the temperature within the chamber 21 between the 600 F. and 900 F. during burner operation, by effecting inter mittent energization of the heater 37 when the tempera ture falls below 600 F. in the chamber. Once the operation of the burner has commenced, then the operation of the band heater 37 may be discontinued. However, if desired, the switch closing the circuit to the band heater may be maintained in its closed position as the thermostat 40 wired into the circuit will automatically cycle the band heater 37 into and out of operation to assure continued gasification of the liquid fuel in a temperature range between 600 F. to 900 F. It will be, of course, understood that suitable controls may be connected into the supply line 26 of the liquid fuel so that the amount or the proportioning of the liquid fuel can be regulated in accordance with the demands being made upon the burner 20.

In the burner described, various grades of fuel oil may be utilized therein. However, in the event that relatively low grade fuel oil, as for example a number 6 grade or lower, is utilized, a means is provided whereby the gasifying chamber 21 may be scavenged at periodic intervals so as to maintain the same readily free of residue which may result during the gasification of such relatively low grade fuels. In accordance with this invention, an igniter means 41 in the form of a glow plug, an electrode, spark plug, or the like is disposed within the chamber 21. The igniter or glow plug 41 is connected into a suitable circuit by which the igniter or glow plug 41 may be intermittently operated at periodic intervals to effect or provide for a controlled combustion to occur directly in the gasifying chamber. Accordingly,

such control combustion directly in the gasifying chamber will consume and residue which may otherwise tend to accumulate therein when relatively low grade fuels are being burned.

The burner construction 20 described may be readily converted into a combination gas and oil burner by connecting to the burner a gas supply pipe 42. In the illustrated embodiment of FIGURE 1, the gas supply conduit 42 is connected directly into the chamber 21. As shown a suitable valve 43 may be interposed in the gas line 42 so as to control the flow of gaseous fuel tochamber 21. Therefore, with the arrangement described either a gas and/or oil may be burned, either separately and/or in combination. Accordingly, it is to be noted that the arrangement described provides that the same burner tip 22A can be utilized for burning either the liquid gasified fuel and/or gas fuel, separately and/or in combination. As a result a separate and distinct burner spud or nozzle is not necessary for burning the respective fuels, as heretofore required. Consequently, the need of separate and distinct burner spuds or nozzles for the respective fuels is completely eliminated with the burner construction of this invention. Also, it is to be noted that the type and amount of the respective fuels which are desired to be consumed can be readily controlled by proportionin-g the same through the valve means 27 and 43 provided and which may be operatively associated with suitable burner controls to effect automatic operation.

FIGURES 4 and 5 illustrate a slightly modified form of the invention. In this form of the invention the construction and operation of the burner arrangement 50 disclosed therein is substantially similar to that described with reference to FIGURES 1 to 3 with the exception that the construction of the air preheating means 51 is slightly modified from that hereinbefore described. In this form of the invention the air preheater means 51 comprises an integrally formed annular chamber 52 formed of a refractory or other suitable heat resistent material. As shown the annular preheater chamber 52 is defined by a substantially cylindrical outer wall 53 circumscri-bing a bottom wall 54; the bottom wall 54 being provided with a central opening 55 through which there is extended the fuel pipe 56. As shown in FIGURE 4, the inner wall 57 of the annular chamber 52 is upwardly and outwardly inclined in a stepped manner to form a plurality of concentrically disposed shoulders or steps 58. A partition wall or baffle 59 extends between the inner and outer wall means 53, 57 to define an internal barrier. The chamber 52 so formed is provided with a pair of nipples, one disposed on either side of the partition. Accordingly, one nipple 60 defines an inlet to the chamber 53 and the other nipple 6-1 defines the outlet of the annular chamber described. Accordingly, a combustion air supply line is connected to the inlet nipple 60, and the discharge nipple 61 is connected by a conduit 62 in communication wit-h the gasifying chamber 63. As shown the air heater chamber 52 is disposed in heat transfer relationship to the burner tip 64 so that the air flowing through the chamber 52 is preheated in a manner as hereinbefore described. Accordingly, the operation and construction of the burner of FIGURES 4 and 5 is similar to that described with respect to FIGURE 1.

If desired, the burner construction of FIGURES l and 4 may be transformed into a space heater by incorporating therewith a mantle construction 65 as shown in FIG- URE 10. This mantle 65 is formed of Inconel mesh which becomes incandescent and thus radiates heat therefrom when placed in heat exchange relationship to the burner tip 64.

FIGURES 6, 7, and 8 illustrate a further modified form of the invention. In this form of the invention the burner 70 is utilized in conjunction with a furnace or combustion chamber 71. Accordingly, the gasifying chamber 72 is remotely disposed to the exterior of the combustion chamber of furnace 71. As hereinbefore described the gasifying chamber 72 comprises an enclosure in which there is provided with a heating band 73 as hereinbefore described. Fuel is supplied therethrough by an oil line 74 and a gas line 75. Also, the gasification chamber 72 is provided with an igniter 76 of the type herein described, and which is adapted for intermittent operation in the event that relatively low grade fuel oils are being gasified in the chamber to effect the cont-r01 combustion necessary to scavenge the gasifying chamber 72 at periodic intervals, as described.

Accordingly, a burner nozzle 77 is connected in communication with the gasifying chamber by means of the fuel pipe 78 through which the combustible mixture is supplied from the gasifying chamber 72 to the burner nozzle 77. In this form of the invention, the air preheating means 79 in the form of a cylindrically shaped annular chamber 80 is spaced about the tip end 81 of the burner nozzle 77 and disposed within the furnace chamber. Accordingly, the cylindrical annular chamber is preferably formed of a heat resistent material, as for example a suitable high temperature refractory and forms a burner or flame throat. The annular chamber is closed at each end by end walls 82, 83 and between each end wall 82, 83 there is extended, longitudinally, a partitioned wall 84 to define the inlet portion of the annulus from the outlet portion thereof. Disposed to either side of the partition 84 is an inlet 85 and outlet opening 86 which are respectively connected to a suitable conduit means through which combustion air is introduced into and out of the annulus 80 during burner operation.

Referring to FIGURE 6, the discharge conduit 87 through which the preheated air is discharged has connected to its outer end a T connection 88. Connected to one end of the T is a branch line 89 that connects to the gasifying chamber 72. The other end .of the T connection 88 is connected by a suitable branch or line 90 that connects to the inlet of the burner nozzle 77. Accordingly, suitable valves 89A, 90A are disposed at each of the branch lines 89, 90 to control and proportion the amount of preheated air directed either to the gasifying chamber 72 and/or to the inlet of the burner nozzle 77.

In this form of the invention, due to the exposure of the air preheater 79 to the high temperature furnace temperatures, all of the air preheated is not required to effect gasification of the liquid fuel supplied to the gasifying chamber. Accordingly, only a portion of the preheated air is directed to the gasifying chamber, the remainder being channeled through branch 90 to the burner where it is mixed or added to the fuel mixture delivered to the burner nozzle through pipe 78 to form the ultimate combustible mixture.

In this form of the invention a glow plug or igniter 91 may also be disposed in the gasifying chamber 72 so as to effect control combustion therein in the event that relatively low grade fuels are being consumed. In all other respects the operation and function of the burner construction of FIGURE 6 is similar to that hereinbefore described.

FIGURE 9 illustrates another burner 100 modification in which the concept is applied to a space heater. As shown, the base 101 of the burner 100 of FIGURE 9 is constructed to define a gasifying chamber 102 as hereinbefore described. The gasifying chamber 102 also is provided with a band heater 101A to effect gasification of the liquid fuel upon start-up of the burner as hereinbefore described. Also, there is provided with an igniter or glow plug 103 to affect periodic scavenging of the gasifying chamber 102 in the event that a relatively low grade fuel oil is being consumed. Connected in communication with the gasifying chamber 102 is the burner nozzle 104.

In this form of the invention an incandescent mantle 105 is supported on the base portion 101 of the burner.

Formed integrally of the mantle are passageways which form the air preheating means by which combustion air is initially preheated prior to its introduction into the gasifying chamber 102. In the illustrated form of the invention the mantle 105 has incorporated therein a pair of vertically spaced annular conduits 106 and 107 circumscribing the mantle and which are inter-connected by a plurality of upright interconnecting conduits 108. Accordingly, the combustion air is introduced into the upper annular conduit 106 by means of a supply conduit 109 which connects to a source of air supply not shown. The air is then distributed from the inlet annular conduit 106 through the respective interconnecting conduits 108 to the lower annular conduit 107. The lower annular conduit 107 in turn is connected into open communication with the gasifying chamber 102. Accordingly, the air heated to a temperature, as hereinbefore described, is intimately mixed with the liquid fuel being introduced through an appropriate supply conduit 110 into the gasifying chamber 102, the heat of the air effecting gasification of the liquid fuel. The combustible mixture thus formed is then supplied to the burner nozzle 104 through the fuel pipe 111.

The operation of the space heater of FIGURE 9 is otherwise identical in function to the embodiments hereinbefore described. If desired, gas may be used as an alternate fuel and it is supplied to the chamber by a supply conduit 112.

From the foregoing description it will be readily apparent that a relatively simple, inexpensive, and positive functioning combination oil and/or gas burner is provided whereby maximum efiiciency of liquid fuel is attained with the same cleanliness of operation afforded by conventional gas burners. Also, the burner construction described renders it readily convenient and feasible for alternating the burning of either a liquid fuel and/ or a gaseous fuel through the same burner nozzle to greatly simplify'the burner construction, its controls, and its operation over combination gas and oil burners heretofore known. Another important characteristic of the instant oil burner is that it can be readily applied to a gas burner installation, as its flue requirements is comparable to that of a conventional gas installation.

While the invention has been described with respect to several embodiments thereof, it will be readily understood and appreciated that variations and modifications thereof may be made without departing from the spirit or scope of the invention.

What is claimed is:

1. A combination gas and oil burner comprising:

(a) means defining a gasifying chamber,

(b) a heating means disposed within said chamber,

(c1)J means for introducing a liquid fuel into said cham- (d) a burner head,

(e) means connecting said burner head in communica-.

tion with chamber,

(f) an air preheating means,

(.g) means for directing a stream of air through said preheating means,

(b) said air preheating means having an outlet end connected in communication with said chamber whereby said air heated therein is directed to said chamber and utilized to gasify said liquid fuel so that the latter is intimately mixed with said heated air to form a combustible mixture,

(i) a gas conduit connected to said chamber to supply a gas to said chamber as an alternate fuel,

(j)means for controlling the flow of said respective fuels to said chamber to proportion the flow of said respective fuels thereto,

(k) and said burner head being common to the burning of said gasified liquid fuel and/ or gas,

(1) and an ignition means in said gasifying chamber whereby said ignition means is intermittently operated to scavenge said chamber in the event a heavy liquid fuel is being used.

2. A combination gas and oil burner comprising:

(a) means defining a gasifying chamber,

(-b) means for introducing a liquid fuel into said chamber,

(c) a heating means disposed within said chamber to effect initial gasification of the liquid fuel supplied thereto,

(d) a burner head,

(e) conduit means connecting said burner head in communication with said chamber,

(f) an air preheating means disposed in heat transfer relationship to said burner head,

(g) means for directing a stream of air through said preheating means,

(h) said preheating means comprising a preheating corrugated conduit encircling said burner head in spaced relationship thereto, said conduit having a ratio of heat exchange surface to air temperature suflicient to preheat said air to a temperature ranging between 600 F. to 900 F.,

(i) said preheating conduit having an outlet end connected in communication with said chamber whereby said heated air entering said chamber is utilized to gasify said liquid fuel during burner operation, said preheated air being intimately mixed with said fuel in said chamber to form a combustible mixture,

(3') a gas conduit supplying a gaseous fuel to said chamher, and

(k) means for controlling the flow of said respective fuels to said chamber to proportion the flow of said respective fuels thereto.

3. An oil burner capable of burning relatively low grade oils comprising:

-(a) a burner means,

(:b) means defining a gasifying chamber,

(c) a means connecting said chamber in communication with said burner means,

(d) an air preheater means dispose-d in heat transfer relationship to said burner means,

(e) means for directing air through said preheater means to heat the same to a temperature ranging between 600 F. and 900 F.,

(f) said preheater means having an outlet connected in communication with said chamber whereby the heated air flowing therethrough is directed to said chamber,

g) means for introducing relatively low grade fuel oil into said chamber whereby the heat of said air flowing through said chamber causes said oil to gasify and intimately mingle with said air to form a combustible gaseous mixture in said chamber,

(h) and an intermittently operated igniter disposed in said chamber whereby said igniter is utilized to periodically scavenge said chamber of any residue accumulating in said chamber at predetermined intervals so that said chamber is maintained relatively free of residue during the operation of said burner.

4. A combination gas and oil burner comprising:

(a a burner means common to burning either gas or relatively low grade fuel oil,

(b) means defining a gasifying chamber,

(c) a means connecting said chamber in communication with said burner means,

((1) an air preheater means disposed in heat transfer relationship to said burner means,

(e) means for directing air through said preheater means to heat the same to a temperature ranging between 600 F. and 900 F.

(f) said preheater means having an outlet connected in communication with said chamber whereby the heated air flowing therethrough is directed to said chamber,

(g) means for introducing relatively low grade fuel oil into said chamber whereby the heat of said air flowing through said chamber causes said oil to gasify and intimately mingle with said air to form a combustible gaseous mixture in said chamber,

(h) and an intermittently operated igniter disposed in said chamber whereby said igniter is utilized to periodically scavenge said chamber of any residue accumulating in said chamber, at predetermined intervals, so that said chamber is maintained relatively clean during the operation of said burner,

(i) means for supplying a gaseous fuel to said burner means,

(j) and means for controlling the flow of said respective fuels to said burner means.

5. A combination gas and oil burner comprising:

(a) means defining a gasifying chamber,

(b) a burner including a burner housing remotely disposed from said chamber,

(c) a burner tip disposed within said housing,

((1) a supply conduit connecting said chamber to said burner tip to supply said tip with a fuel mixture,

(e) a combustion air preheater disposed within said housing in heat transfer relationship to said burner p,

(f) said air preheater having a heat exchange surface to air temperature ratio sufficient to maintain said heated air at a temperature ranging between 600 F to 900 F.,

(g) said preheater having an outlet connected in communication with said gasifying chamber so that all the air heated flowing therethrough is directed to said chamber,

(h) means supplying a liquid fuel into said chamber whereby the mixture of said liquid fuel with said heated air effects gasification of the liquid fuel and intricate mixing of the same with said air to form a combustible mixture,

(i) and an intermittently operated igniter disposed in said chamber whereby the intermittent operation of said igniter effects controlled ignition of said combustible mixture therein to effect a periodic cleaning of said chamber.

6. The invention as defined in claim 5 and including a means for supplying a gaseous fuel to said chamber whereby a combination of gasified liquid fuel and/or gas may be burned.

7. The invention as defined in claim 5 wherein said burner tip comprises:

(a) a ceramic spud substantially circular in horizontal cross-section with upwardly and outwardly flaring surrounding sidewalls,

(b) said spud having an inlet adapted to be connected to said supply conduit,

(c) means defining an internal distributing chamber in said spud,

(d) and a plurality of radially extending channels extending between said distributing chamber and the sidewalls of said spud to define therein a plurality of circumferentially spaced port openings therein.

8. The invention as defined in claim 5 wherein said preheater comprises:

(a) an integrally formed annulus of fire resistant material,

(b) said annulus having a substantially cylindrical outer wall portion, and a stepped inner wall portion, (c) said inner wall being stepped upwardly and out wardly toward said outer wall,

(d) and a vertical partition located between said inner and outer wall,

(e) and means defining an inlet and outlet to said annulus disposed on opposite sides of said partition.

9. The invention as defined in claim 8 wherein said annulus is formed of a ceramic material.

10. A combination oil and gas burning space heater comprising:

(a) a base defining a gasifying chamber,

(b) a heater disposed within said chamber,

(c) a mantel extending upwardly from said base,

(d) a preheater including a pair of circumscn'bing conduits vertically spaced about said mantel in heat transfer relationship thereto,

(e) a plurality of circumferentially spaced interconnecting conduits connecting said pair of circumscribing conduits in communication, one of said circumscribing conduits being connected in communication with said chamber,

(f) a burner disposed within said mantel connected in communication with the interior of said chamber, (g) means for supplying a liquid fuel to said chamber, (11) means for supplying air through said preheater member whereby said air is circulated to said conduits and introduced into said chamber to mix with and gasify the liquid fuel within said chamber to form a combustible mixture,

(i) said mixture being directed to said burner means,

(1') and an igniter disposed in said chamber to periodically scavenge said chamber.

11. A combination oil and gas burning space heater comprising:

(a) a base defining a gasifying chamber,

(b) a heater disposed within said chamber,

(c) an annulus conduit connected to said base,

(d)v means connecting said annulus conduit in communication with said chamber,

(e) a mantel extending upwardly from said annulus member,

(f) a second annulus conduit circumscribing said mantel adjacent the upper end thereof,

(g) a plurality of circumferentially spaced interconnecting conduits connecting said annulus conduits in communication,

(h) a burner connected in communication with the interior of said chamber,

(i) means for supplying a liquid fuel to said chamber,

(j) means to supplying combustion air to said second annulus conduit whereby said air is circulated to said conduits and introduced into said chamber to mix with and gasify the liquid fuel introduced into said chamber to form a combustible mixture,

(k) said mixture being directed to said burner means,

(1) an igniter disposed in said chamber, said igniter being intermittently operated to periodically scavenge said chamber.

12. A combination oil and gas burning space heater comprising (a) a base defining a gasifying chamber,

(b) a burner connected in communication with said chamber,

(c) an incandescent mantle supported on said base,

said mantle circumscribing said burner,

(d) means formed in said mantle to define passageways therein through which combustion air is permitted to flow whereby said air is preheated as it flows therethrough,

(e) means connecting said passageways in communication with said gasifying chamber,

(f) means for introducing a liquid fuel into said chamber whereby the mixture of said fuel with said pre heated air causes said fuel to be gasified,

(g) and means for periodically igniting said mixture in said chamber to effect a periodic cleansing of said chamber,

(h) and means for introducing a gaseous fuel into said chamber whereby said gas may be burned as an alternate fuel.

13. A space heater comprising:

(a) a base defining a gasifying chamber,

(b) a burner connected in communication with said chamber,

(c) an incandescent mantle supported on said base,

said mantle circumscribing said burner,

(d) means formed in said mantle to define passageways through which combustion air is permitted to flow to preheat the same,

(e) means connecting said passageways in communication with said gasifying chamber so that said preheated air is introduced into said chamber,

(f) means for introducing a liquid fuel into said chamber whereby the mixture of said fuel with said preheated air causes said fuel to be gasified,

(g) and means for periodically igniting said mixture in said chamber to effect a periodic scavenging of said chamber,

14. A combination oil and gas burner comprising:

(a) a gasifying compartment adapted to be remotely disposed from a combustion chamber,

(b) an igniting means disposed in said compartment,

(c) means for supplying a liquid fuel to said compartment,

(d) a burner having a tip end,

(e) a conduit connecting said compartment to said burner for directing a fuel mixture to said burner, (f) means for elfecting the gasification of said liquid fuel within said compartment,

(g) said latter means including a tubular annulus dis:

posed about the tip of said burner,

(h) means for directing air to said annulus whereby said air is heated therein by indirect heat transfer from the flame at said burner tip,

(i) a conduit discharging said' heated air from said annulus,

(j) a branch connected to said discharging conduit for directing said heated air to said compartment,

(k) a second branch connected to said discharging conduit for directing said heated air to said burner, and

(1) means for controlling the fiow 'of heated air through the respective conduits.

15. The invention as defined in claim 14 and including means for introducing a gas into said compartment as an alternate fuel.

16. A combination oil and gas burner comprising:

(a) means defining a combustion chamber,

(b) a gasifying compartment remotely disposed from a combustion chamber,

(c) an igniting means disposed in said compartment,

(d) means for supplying a liquid fuel to said compartment,

(e) a burner having a tip end disposed in said combustion chamber,

(f) a conduit connecting said compartment to said burner for supplying a combustible fuel mixture to said burner tip,

(g) means for effecting the gasification of said liquid fuel in said compartment,

(b) said latter means including a flexible corrugated tubular member disposed about said burner tip within said combustion chamber,

(i) means for directing air at ambient air temperature through said tubular member, said tubular member having ratio of heating surface to air temperature sufficient to heat the air passing therethrough to a temperature in the range of 600 F. to 900 F.,

(j) said tubular member having a discharge end directing said heated air into said compartment whereby said heated air efiects a gasification of the liquid fuel in said compartment,

(k) a heater disposed in said compartment for effecting initial gasification of said liquid fuel on start-up of said burner,

(l) thermostatic means for controlling the temperature 13 within said compartment between 600 F. and 900 F.,

(111) said igniter being intermittently operated to periodically scavenge said compartment when low grade fuel oils are being burned,

(n) and means for supplying a gaseous fuel to said compartment as an alternate fuel, whereby said fuels are burned at said tip.

17. An oil burner capable of burning relatively low grade oils comprising:

a burner means,

means defining a gasifying chamber,

means connecting said chamber in communication with said burner means,

an air preheater means,

means directing air through said preheater means to preheat the same to a temperature ranging between 600 F. and 900 F.,

said preheater means having an outlet connected in communication with said chamber whereby the heated air flowing therethrough is directed to said chamber,

means for introducing fuel oil into said chamber whereby the heat of said air flowing through said chamber causes said oil to gasify and intimately mingle with said air to form a combustible, gaseous mixture in said chamber,

5 and an intermittently operated igniter disposed in said chamber whereby said igniter is utilized to periodically scavenge said chamber of any residue accumulating in said chamber at a predetermined interval so that said chamber is maintained relatively free of 10 residue during the operation of said burner.

References Cited by the Examiner UNITED STATES PATENTS 1,535,815 4/1925 Cunningham 158-11 X 15 2,735,481 2/1956 Reichhelm 1585 3,238,991 3/1966 Goldmann 6t a1 158--5 DONLEY J. STOCKING, Primary Examiner.

20 FREDERICK L. MATTESON, JR., Examiner.

E. G. FAVORS, Assistant Examiner. 

1. A COMBINATION GAS AND OIL BURNER COMPRISING: (A) MEANS DEFINING A GASIFYING CHAMBER, (B) A HEATING MEANS DISPOSED WITHIN SAID CHAMBER, (C) MEANS FOR INTRODUCING A LIQUID FUEL INTO SAID CHAMBER, (D) A BURNER HEAD, (E) MEANS CONNECTING SAID BURNER HEAD IN COMMUNICATION WITH CHAMBER, (F) AN AIR PREHEATING MEANS, (G) MEANS FOR DIRECTING A STREAM OF AIR THROUGH SAID PREHEATING MEANS, (H) SAID AIR PREHEATING MEANS HAVING AN OUTLET END CONNECTED IN COMMUNICATION WITH SAID CHAMBER WHEREBY SAID AIR HEATED THEREIN IS DIRECTED TO SAID CHAMBER AND UTILIZED TO GASIFY SAID LIQUID FUEL SO THAT THE LATTER IS INTIMATELY MIXED WITH SAID HEATED AIR TO FORM A COMBUSTIBLE MIXTURE, (I) A GAS CONDUIT CONNECTED TO SAID CHAMBER TO SUPPLY A GAS TO SAID CHAMBER AS AN ALTERNATE FUEL, (J) MEANS FOR CONTROLLING THE FLOW OF SAID RESPECTIVE FUELS TO SAID CHAMBER TO PROPORTION THE FLOW OF SAID RESPECTIVE FUELS THERETO, (K) AND SAID BURNER HEAD BEING COMMON TO THE BURNING OF SAID GASIFIED LIQUID FUEL AND OR GAS, (L) AND AN IGNITION MEANS IN SAID GASIFYING CHAMBER WHEREBY SAID IGNITION MEANS IS INTERMITTENTLY OPERATED TO SCAVENGE SAID CHAMBER IN THE EVENT A HEAVY LIQUID FUEL IS BEING USED. 